Analog Devices,inc.

Ronald A Kapusta, Jr

Katsufumi Nakamura

Katsu Nakamura

Doris Lin

Colin Gerard Lyden

Christopher Peter Hurrell

Lawrence A Singer

Jianrong Chen

Eitake Ibaragi

Hiroto Shinozaki

Jianrong (Pierce) Chen

In one aspect, a method of reducing power consumption in a circuit by adaptive bias current generation of a bias current configured to bias, at least in part, at least one amplifier of the circuit is provided. The method comprises establishing the bias current based, at least in part, on a reference frequency of a reference clock providing a clock signal to at least one component of the circuit, and changing the bias current in response to a change in the reference frequency of the at least one reference clock, the bias current being change non-linearly with respect to the change in the reference frequency of the at least one reference clock. In another aspect, the method comprises establishing the bias current based, at least in part, on a capacitance of a reference capacitor, and changing the bias current in response to a change in the capacitance of the reference capacitor such that the bias current is changed non-linearly with respect to changes in the capacitance of the reference capacitor.

Adaptive bias current generator methods and apparatus

An apparatus and method for inter-channel data exchange in multi-channel data acquisition systems is disclosed. A multi-channel data acquisition system may include a data exchange layer coupling two or more channels of the data acquisition system. Data may be transmitted via the data exchange layer between the channels, enabling data from one channel to be processed and output by another channel. The data exchange layer may include a serial exchange layer or a parallel exchange layer.

Data exchange between channels in a data acquisition system

Embodiments of the present invention provide an apparatus and control method for an analog front end (AFE) amplifier for controlling DC restore operations. According to the exemplary method, a first input stage of the AFE is controlled to operate as a continuous time amplifier that has high input impedance and draws substantially no input leakage current for a first predetermined area of an imaging sensor image array. The first input stage is controlled to operate as a sample and hold amplifier with DC restore functionality for a second predetermined area of the imaging sensor image array. According to an embodiment, the AFE input stage operates as a continuous time amplifier when reading pixels from the sensor's active image array but operates as a sample and hold amplifier with DC restore when reading pixels from the image array that correspond to so-called 'black-level' pixels or pixels that otherwise fall outside the sensor's active image field.

Switched capacitor input stage for imaging front-ends

The invention is directed to an interface circuit for bridging voltage domains. The interface circuit receives an input signal, having a larger voltage domain, and safely provides the signal to an electronic device which has a smaller voltage domain. The interface circuit may include a transistor configured as a source follow so that an output of the transistor follows the input of the transistor. A blocking voltage may be provided at the input of the transistor to provide a voltage bias, blocking a range of input voltages to the transistor. The transistor may also have a blocking voltage at a drain terminal of the transistor, to block any output voltage above the blocking voltage.

Interface circuit for bridging voltage domains

The invention is directed to a circuit and method for equalizing digital interference. A digital interference equalizing circuit may include a signal clipping unit, receiving a digital signal and clipping the digital signal based upon a clipping function, and a dithering unit adding dither to the clipped digital signal. A digital interference equalizing circuit may also include a noise detection circuit, detecting the normal activity level in a digital signal which may then be used to scale the dither added to the digital signal.

Dithering technique for reducing digital interference

An analog amplifier includes at least one signal path. Each of the at least one signal path extends between an input and an output and includes a load device coupled to the output and a transistor coupled to the input. The analog amplifier further includes a dither current source selectively coupled to one of the at least one signal path. The dither current source is capable of supplying dither current to the load device of the selected signal path directly by bypassing the transistor of the selected signal path.

Amplifier with dither

Devices and methods for varying individual periods or cycle times of upconverted clock signals within a corresponding reference clock cycle are disclosed. In some embodiments, these varying cycle times may improve signal synchronization between the upconverted clock and the reference clock. In different embodiments, different types of counters and counting circuits keep track of the number of elapsed upconverted clock cycles in order to determine the specific upconverted clock cycles with longer cycle times. In some embodiments, a signal may be sent to a delay line to change the amount of delay between upconverted clock pulses, thereby increasing or decreasing a specific upconverted clock cycle time or period. In some embodiments the specific upconverted clock cycle(s) changed in each reference clock cycle may vary, which may further improve reconciliation between the upconverted clock cycles and the corresponding reference clock cycle.

Calibrating multiplying-delay-locked-loops (MDLLS)

An analog to digital converter comprising an Nth analog to digital converter and an N+1th analog to digital converter arranged in series such that a residue signal from the Nth analog to digital converter is provided as an input to the N+1th analog to digital converter, characterized in that a bandwidth control means is provided in a signal path for the residue signal and the bandwidth control means is controlled so as to have a first bandwidth during a first period following generation of a conversion result from the Nth analog to digital converter, and a second bandwidth less than the first bandwidth in a second period following the first period.

Analog to digital converter

Some embodiments provide real-time variable delays in a delay line. In some of these embodiments, the real-time variable delays may be enable without producing clock glitches. In an embodiment, delay cells in a delay line may be coupled together in a chain to form a lattice of inverters providing different paths of signal propagation. Each path may have a different number of inverters; each inverter adding a known processing time associated with the signal inversion process. In some embodiments, an input signal may be propagated in an inverted or non-inverted form to the inputs of multiple inverters in the lattice, including the inputs of inverters through which the input signal does not propagate. A desired delay time may be obtained in an embodiment by selecting a path containing a desired number and configuration of inverters. The path may be selected in an embodiment using switchably enabled inverters.

Digital delay lines

Two or more buffers may configured and arranged such that a quiescent current that flows through and biases a first buffer also flows through and biases a second buffer. The first and second buffers may, for example, be source followers used as reference buffers that drive inputs of a switched-capacitor circuit.

Stacked buffers

In one aspect, a resistor process invariant transconductor is provided. The transconductor comprises a voltage input configured to receive at least one voltage signal, a current output configured to provide at least one current signal, wherein a ratio between the at least one voltage signal and the least one current signal forms a total transconductance for the transconductor, and a circuit including at least one integrated resistor connected between the voltage input and the current output, the circuit adapted to maintain the total transconductance substantially constant across variation of the at least one integrated resistor.

Methods and apparatus for process invariant transconductance

In one embodiment, a circuit comprises at least first and second circuit stages, at least one level shifting circuit, and a control circuit. The first circuit stage is configured and arranged to produce a reference voltage at the at least one first output during each first phase of at least first and second phases, and to produce an output signal at the at least one first output that is responsive to an input signal at the at least one first input during each second phase of the at least first and second phases. The at least one level shifting circuit comprises at least one capacitor and at least one switch and is coupled between the first circuit stage and the second circuit stage. The control circuit is configured to control the level shifting circuit such that, during each first phase, respective plates of the at least one capacitor are connected to the at least one first output of the first circuit stage and a source of a substantially constant voltage so as to allow the at least one capacitor to be charged to a level-shift voltage equal to a difference between the substantially constant voltage and the reference voltage, and such that, during each second phase, the respective plates of the at least one capacitor are connected to the at least one first output and the at least one second input to thereby introduce the level-shift voltage across the at least one capacitor as an offset voltage therebetween.

Switch-capacitor techniques for level-shifting

Methods and apparatus for reducing the thermal noise integrated on a storage element are disclosed. One embodiment of the invention is directed to a sampling circuit comprising a sampling capacitor to store a charge, the sampling capacitor being exposed to an ambient temperature. The sampling circuit further comprises circuitry to sample the charge onto the capacitor, wherein thermal noise is also sampled onto the capacitor, and wherein the circuitry is constructed such that the power of the thermal noise sampled onto the capacitor is less than the product of the ambient temperature and Boltzmann's constant divided by a capacitance of the sampling capacitor. Another embodiment of the invention is directed to a method of controlling thermal noise sampled onto a capacitor. The method comprises an act of independently controlling the spectral density of the thermal noise and/or the bandwidth of the thermal noise.

Growing community of inventors

Waltham, MA, United States of America

Ronald A Kapusta, Jr